High responsivity and flexible deep-UV phototransistor based on Ta-doped β-Ga2O3

Abstract

Deep-ultraviolet (DUV) phototransistors have shown great potential applications in UV imaging, artificial intelligence, and wearable optoelectronics. Among a large number of wide bandgap semiconductors, the quasi-two-dimensional β-Ga₂O₃ is considered as an ideal candidate for DUV photodetector applications. Herein, we report a high responsivity (R) and fully flexible Ta-doped β-Ga₂O₃ DUV phototransistor which exhibits outstanding optoelectrical properties with a high R of 1.32 × 10⁶ A/W, a large detectivity of 5.68 × 10¹⁴ Jones, a great photo-to-dark current ratio of 1.10 × 10¹⁰%, a high external quantum efficiency of 6.60 × 10⁸%, and an ultra-fast response time of ~3.50 ms. Besides, the flexible Ta-doped β-Ga₂O₃ device also displays high reliability and mechanical flexibility that can sustain well after over 1 × 10⁴ bending cycles. Moreover, high-contrast imaging of UV light was obtained on the flexible DUV detector arrays, which can be efficiently trained and recognized by an artificial neural network. Our findings offer a perspective to develop wearable optoelectronics and UV imaging based on high-performance flexible β-Ga₂O₃ DUV phototransistors, providing an inspiration for the future work in artificial intelligence and bionic robot fields.